glsl-conditionals

Daniel Holden's functions designed to avoid conditionals in GLSL, available both as ES modules strings and as GLSL files for use with glslify.

Disclaimer: you might not need this as it is highly hardware dependant and branching might not equate more operations in modern GPUs. Also it can make your shader harder to visually parse.

Installation

npm install glsl-conditionals

Usage

ESM

import * as glslConditionals from "glsl-conditionals";

const shader = /* glsl */ `
// Comparisons
${glslConditionals.WHEN_EQ}
${glslConditionals.WHEN_NEQ}

${glslConditionals.WHEN_GT}
${glslConditionals.WHEN_LT}

${glslConditionals.WHEN_GE}
${glslConditionals.WHEN_LE}

// Logical operators
${glslConditionals.WHEN_AND}
${glslConditionals.WHEN_OR}
${glslConditionals.WHEN_XOR}
${glslConditionals.WHEN_NOT}

void main() {
  float x = 10.0;
  float y = 0.0;

  y += 5.0 * when_eq(x, 0.0);
  y += 5.0 * when_eq(x, 0.0);
  y += 5.0 * when_neq(x, 0.0);
  y += 5.0 * when_gt(x, 0.0);
  y += 5.0 * when_lt(x, 0.0);
  y += 5.0 * when_ge(x, 0.0);
  y += 5.0 * when_le(x, 0.0);
  y += 5.0 * when_and(x, 0.0);
  y += 5.0 * when_or(x, 0.0);
  y += 5.0 * when_xor(x, 0.0);
  y += 5.0 * when_not(x, 0.0);

  // ...
}
`;

glslify

// Comparisons
#pragma glslify: when_eq = require(glsl-conditionals/when_eq)
#pragma glslify: when_neq = require(glsl-conditionals/when_neq)

#pragma glslify: when_gt = require(glsl-conditionals/when_gt)
#pragma glslify: when_lt = require(glsl-conditionals/when_lt)

#pragma glslify: when_ge = require(glsl-conditionals/when_ge)
#pragma glslify: when_le = require(glsl-conditionals/when_le)

// Logical operators
#pragma glslify: when_and = require(glsl-conditionals/when_and)
#pragma glslify: when_or = require(glsl-conditionals/when_or)
#pragma glslify: when_xor = require(glsl-conditionals/when_xor)
#pragma glslify: when_not = require(glsl-conditionals/when_not)

void main() {
  float x = 10.0;
  float y = 0.0;

  y += 5.0 * when_eq(x, 0.0);
  y += 5.0 * when_eq(x, 0.0);
  y += 5.0 * when_neq(x, 0.0);
  y += 5.0 * when_gt(x, 0.0);
  y += 5.0 * when_lt(x, 0.0);
  y += 5.0 * when_ge(x, 0.0);
  y += 5.0 * when_le(x, 0.0);
  y += 5.0 * when_and(x, 0.0);
  y += 5.0 * when_or(x, 0.0);
  y += 5.0 * when_xor(x, 0.0);
  y += 5.0 * when_not(x, 0.0);

  // ...
}

License

MIT. See license file.